What was found
AFTER GEAR RETRACTION BOTH LEFT EFIS TUBES WENT BLACK, AFTER HYDRAULIC PUMP STOPPED RUNNING AND BOTH LEFT TUBES CAME BACK. FIVE MINUTES INTO FLIGHT EFIS TUBES WENT BLACK AGAIN, FOLLOWED QRH, SHUTDOWN LEFT GENERATOR. AIRCRAFT RETURNED TO DTW. MAINTENANCE REPLACED LEFT STARTER/DC GEN. RAN AIRCRAFT, ALL CHECKS GOOD.